I had a chance to talk to Robert Hunter for a short time between sets of a solo show he did in Iowa City back in the early 80's. And we shook hands, so I shook the hand that wrote the words!! That is if he is right handed. If he is left handed there goes my cosmic Dead poetic connection fantasy.
I seem to remember in the Box Of Rain book, Hunter mentioned typing Terrapin Station, so he probably wrote a lot of lyrics that way. Seeing as how that usually takes both hands, I think your fantasy is safe and intact.